“We have discovered a unique defensive tactic of juvenile Japanese eels using an X-ray video system: they escape from the predator’s stomach by moving back up the digestive tract towards the gills after being captured by the predatory fish,” said Yuuki Kawabata of Nagasaki University in Japan. “This study is the first to observe the behavioral patterns and escape processes of prey within the digestive tract of predators.”

In an earlier study, the researchers including Kawabata and Yuha Hasegawa had shown that Japanese eels can escape from the gill of their predator after capture. What they didn’t know was how.

“We had no understanding of their escape routes and behavioral patterns during the escape because it occurred inside the predator’s body,” Hasegawa says.

In the new study, they found a way to see inside the predatory fish (Odontobutis obscura) using an X-ray videography device. To visualize the eel after it had been eaten, they had to first inject them with a contrast agent. It still took the team a year to capture convincing video evidence showing the escape process involved.

Their videos show that all 32 captured eels had at least part of their bodies swallowed into the stomach of their fish predators. After being swallowed, all but four tried to escape by going back through the digestive tract toward the esophagus and gills, they report. Of those, 13 managed to get their tails out the fish gill, and nine successfully escaped through the gills. On average, it took the escaping eels about 56 seconds to free themselves from the predator’s gills.

“The most surprising moment in this study was when we observed the first footage of eels escaping by going back up the digestive tract toward the gill of the predatory fish,” Kawabata says. “At the beginning of the experiment, we speculated that eels would escape directly from the predator’s mouth to the gill. However, contrary to our expectations, witnessing the eels’ desperate escape from the predator’s stomach to the gills was truly astonishing for us.”

Further study found that, despite the similarities, the eels didn’t always rely on the same escape route through the gill cleft. Some of them also circled along the stomach, seemingly in search of a way out. The findings are the first to show that the eel Anguilla japonica can use a specific behavior to escape from the stomach and gill of its predator after being eaten. It’s also the first time any study has captured the behaviors of any prey inside the digestive tract of its predator, according to the researchers.

The researchers say that the X-ray methods used in the study can now be applied to observations of other predator-prey behaviors. In future work, they hope to learn more about the characteristics that make for a successful escape by the eels.

Nearly 7 million Americans are living with Alzheimer’s disease, the fifth leading cause of death among those 65 and older. The disease will carry an estimated $360 billion in health care costs this year alone, according to the Alzheimer’s Association.

Researchers led by Duke Han, professor of psychology and family medicine at USC Dornsife, aimed to better understand the link between early Alzheimer’s disease and financial vulnerability by using high-powered MRI to examine the brains of 97 study participants over age 50.

The scientists focused on the entorhinal cortex, a region that acts as a relay station between the hippocampus — the brain’s learning and memory center — and the medial prefrontal cortex, which regulates emotion, motivation and other cognitive functions. It is often the first region to show changes in Alzheimer’s disease, typically becoming thinner as the disease progresses.

None of the study participants, age 52 to 83, showed clinical signs of cognitive impairment, but all underwent MRI scans to measure the thickness of their entorhinal cortex.

In addition, the researchers used a standardized tool called a Perceived Financial Exploitation Vulnerability Scale (PFVS) to assess the participants’ financial awareness and their susceptibility to poor financial decisions, which they term “financial exploitation vulnerability,” or FEV.

By comparing the adults’ FEV with the thickness of their entorhinal cortex, Han and the team found a significant correlation: Those more vulnerable to financial scams had a thinner entorhinal cortex.

This was especially true for participants age 70 and older. Previous research has linked FEV to mild cognitive impairment, dementia and certain molecular brain changes associated with Alzheimer’s disease.

Han, who holds a joint appointment at Keck School of Medicine of USC, says the findings provide crucial evidence supporting the idea that FEV could be a new clinical tool for detecting cognitive changes in older adults — changes that are often difficult to detect.

“Assessing financial vulnerability in older adults could help identify those who are in the early stages of mild cognitive impairment or dementia, including Alzheimer’s disease,” Han said. He added, however, that financial vulnerability alone is not a definitive indicator of Alzheimer’s disease or other cognitive decline. “But assessing FEV could become part of a broader risk profile,” he said.

Han also noted several limitations of the study. Most participants were older, white, highly educated women, making it difficult to generalize the findings to a more diverse population. Additionally, while the study found a link between entorhinal cortex thickness and FEV, it does not prove one. Finally, the study does not include specific measures of Alzheimer’s disease pathology.

These limitations leave open the possibility that the relationship between FEV and entorhinal cortex thinning could be explained by other factors. Accordingly, Han said that more research, including long-term studies with diverse populations, is needed before FEV can be considered a reliable cognitive assessment tool.

The method, leveraging a solvent of sodium hydroxide and urea in water, can significantly lower the production cost of nanocellulosic fiber — a strong, lightweight biomaterial ideal as a composite for 3D-printing structures such as sustainable housing and vehicle assemblies. The findings support the development of a circular bioeconomy in which renewable, biodegradable materials replace petroleum-based resources, decarbonizing the economy and reducing waste.

Colleagues at ORNL, the University of Tennessee, Knoxville, and the University of Maine’s Process Development Center collaborated on the project that targets a more efficient method of producing a highly desirable material. Nanocellulose is a form of the natural polymer cellulose found in plant cell walls that is up to eight times stronger than steel.

The scientists pursued more efficient fibrillation: the process of separating cellulose into nanofibrils, traditionally an energy-intensive, high-pressure mechanical procedure occurring in an aqueous pulp suspension. The researchers tested eight candidate solvents to determine which would function as a better pretreatment for cellulose. They used computer models that mimic the behavior of atoms and molecules in the solvents and cellulose as they move and interact. The approach simulated about 0.6 million atoms, giving scientists an understanding of the complex process without the need for initial, time-consuming physical work in the lab.

The simulations developed by researchers with the UT-ORNL Center for Molecular Biophysics, or CMB, and the Chemical Sciences Division at ORNL were run on the Frontier exascale computing system — the world’s fastest supercomputer for open science. Frontier is part of the Oak Ridge Leadership Computing Facility, a DOE Office of Science user facility at ORNL.

“These simulations, looking at every single atom and the forces between them, provide detailed insight into not just whether a process works, but exactly why it works,” said project lead Jeremy Smith, director of the CMB and a UT-ORNL Governor’s Chair.

Once the best candidate was identified, the scientists followed up with pilot-scale experiments that confirmed the solvent pretreatment resulted in an energy savings of 21% compared to using water alone, as described in the Proceedings of the National Academy of Sciences.

With the winning solvent, researchers estimated electricity savings potential of about 777 kilowatt hours per metric ton of cellulose nanofibrils, or CNF, which is roughly the equivalent to the amount needed to power a house for a month. Testing of the resulting fibers at the Center for Nanophase Materials Science, a DOE Office of Science user facility at ORNL, and U-Maine found similar mechanical strength and other desirable characteristics compared with conventionally produced CNF.

“We targeted the separation and drying process since it is the most energy-intense stage in creating nanocellulosic fiber,” said Monojoy Goswami of ORNL’s Carbon and Composites group. “Using these molecular dynamics simulations and our high-performance computing at Frontier, we were able to accomplish quickly what might have taken us years in trial-and-error experiments.”

The right mix of materials, manufacturing

“When we combine our computational, materials science and manufacturing expertise and nanoscience tools at ORNL with the knowledge of forestry products at the University of Maine, we can take some of the guessing game out of science and develop more targeted solutions for experimentation,” said Soydan Ozcan, lead for the Sustainable Manufacturing Technologies group at ORNL.

The project is supported by both the DOE Office of Energy Efficiency and Renewable Energy’s Advanced Materials and Manufacturing Technologies Office, or AMMTO, and by the partnership of ORNL and U-Maine known as the Hub & Spoke Sustainable Materials & Manufacturing Alliance for Renewable Technologies Program, or SM2ART.

The SM2ART program focuses on developing an infrastructure-scale factory of the future, where sustainable, carbon-storing biomaterials are used to build everything from houses, ships and automobiles to clean energy infrastructure such as wind turbine components, Ozcan said.

“Creating strong, affordable, carbon-neutral materials for 3D printers gives us an edge to solve issues like the housing shortage,” Smith said.

It typically takes about six months to build a house using conventional methods. But with the right mix of materials and additive manufacturing, producing and assembling sustainable, modular housing components could take just a day or two, the scientists added.

The team continues to pursue additional pathways for more cost-effective nanocellulose production, including new drying processes. Follow-on research is expected to use simulations to also predict the best combination of nanocellulose and other polymers to create fiber-reinforced composites for advanced manufacturing systems such as the ones being developed and refined at DOE’s Manufacturing Demonstration Facility, or MDF, at ORNL. The MDF, supported by AMMTO, is a nationwide consortium of collaborators working with ORNL to innovate, inspire and catalyze the transformation of U.S. manufacturing.

Other scientists on the solvents project include Shih-Hsien Liu, Shalini Rukmani, Mohan Mood, Yan Yu and Derya Vural with the UT-ORNL Center for Molecular Biophysics; Katie Copenhaver, Meghan Lamm, Kai Li and Jihua Chen of ORNL; Donna Johnson of the University of Maine, Micholas Smith of the University of Tennessee, Loukas Petridis, currently at Schrödinger and Samarthya Bhagia, currently at PlantSwitch.